Sound insulation board



March 4, 1952 P. A. PALMER 2,587,834

SOUND INSULATION BOARD Filed Feb. 5, 1947 un-n.

Patented Mar. 4, 1952 SOUND INSULATION BOARD Per Anders Palmer, Stockholm, Sweden Application February 5, 1947, Serial No. 726,551 In Sweden October 30, 1945 5 Claims.

The main object of the present invention is to provide a sound insulation board, particularly for ceilings or walls, which effectively absorbs sound and at the same time enables air ventilation of the buildings in which the board, is arranged.

A further object of the invention is to provide a hard, perforated plate or panel which has a self-vibration in response to tones of low frequency, whereby a more advantageous absorption of sound for the structure as a whole is obtained. Preferably, the hard plate forms, on one side (the rear side) strengthening braces, between which sound absorbing cushions are arranged.

A still further object of the invention is to provide a number of perforations in the plate, some of these perforations leading to the sound absorb,- ing cushions while other perforations by means of passages extending transversely through the board communicate with a free space at the rear side of the plate for the purpose of air ventilation so that the air can pass through the latter perforations of the plate without passing through the sound absorbin cushions.

A further object of the invention is to substitute the perforations leading to the sound ab,- SOIbiIlg cushions by thin diaphragms or attenuations, which, without being perforated, facilitate the conduction of the sound into the cushions.

Further objects and features of the invention will appear from thefollowing description with reference to the accompanying drawing in which Figures 1 and 2 show fragmental views of two embodiments of the board according to the invention in vertical section. Figure 3 is a fragmental plan view of Figure 2 as viewed from the bottom side of the board. Fig. 4 is a detail view of Fig. 2 on a larger scale.

Referring first to Figure 1 the sound. insulating board consists of a plate I, for example of mill-board, asbestos, sheet metal or the like, in which apertures, slits passages or perforations 2 are arranged at suitable intervals and of suitable size for producing the desired rate of selfvibration of the board. Around the plate I is moulded a non-inflammable hard mass 3, for instance of plaster or cement, in which perforations or passages 4 are made, e. g. by drilling or moulding on cores. The perforations or slits 2 in the plate I register with the perforations 4. The mass 3 may, if desired, form strengthening laths, beams or braces 5, through which channels or passages 6 extend to the rear side of the board,

and in which vertical portions or walls Ia bent up from the plate I or attached to the plate I form strengthening cores. Between the said braces 5 there are arranged sound-absorbing bodies or cushions I of porous material, for instance of slag wool, rockwool, spun glass, seaweed or other fibrous material. The perforations I extend up to the said cushions, so that the sound is led into the latter and is effectively absorbed. The cushions may be provided with slits or recesses so as to loosen the porous mass, said slits or recesses registering with the perforations 4. The

plate I has perforations 2a, registering with the passages 6. The moulded mass 3 forms a cover So on the rear side of the cushions 'I.

It should be noted that if desired the plate I may be dispensed with, in which case the mass 3 is moulded or attached to the cushions I directly.

The plate board thus composed is suspended in some suitable way, for example from a ceiling 8, preferably so as to leave a free space 9 between the ceiling and the board. The suspension can be arranged, for example, by clamps II which are clamped, or securely fixedwith pins I or other such means, to T-bars I2 of sheet-iron or other supports. The horizontal flanges of the T-bars I2 are provided with holes I3 registering with the passages 6, and at certain intervals, with self-threading or other screws I4 or the 1ike so that the board is supported firmly. The clamps ID are suspended on bars I5, which at their ends may be fixed to the walls I6 bysuitable fittings I1, and which moreover may be anchored to the ceiling 8 by holding members such as, wires I78. Sleeves 19 may be arranged to: join or lengthen the bars I5. The passages or channels 6 may be used for the supply of fresh air from; the; space 9 to the room or buildings in which the board. is arranged or for the expulsion of air the reverse way. To this purpose the space communicates with a suitable pipe or vent 20 forthe supply or escape of the air. It should be noted that the air flowing through the passages; 6, does not stream through the cushions I and that the perforations 2 and 4 may be arranged and dimensioned independently of the passages 6.

In the embodiment according to Figure 2 the board comprises a plate 22 of sheet metal, plastic or other material having attenuations 2| distributed in suitable manner. On the rear side the plate 22 may have carriers 23 for carrying the sound-absorbing cushions 24 so that a space 25 is formed between the cushion 24 and the plate 22 and at the sides of the cushion. This space 25 communicates with the air space 9 described with reference to Figure 1, and the air may pass through perforations 28 in the plate 22. By adjusting the size of the cushions 24 the amount of air passing through the space 25 may be con trolled in the desired manner.

The board is suspended in resilient hooks 26 or the like which are clamped to the clamps l described in connection withFigure 1.

The attenuations 2! may be produced by a stamping or pressing operation. The thickness at these places may for instance be mm. It is also possible to produce such attenuations by first perforating the plate 22 and then covering the external face of the apertures thus produced by means of a thin diaphragm, say of metal foil, paper or the like.

What I claim is:

1. A sound insulating device for buildings comprising in combination a board, spaced walls of hard material extending transversely of the board and arranged perpendicularly thereto, means for attaching said board to the fixed structure of the building with the front surface of the board facing the interior of a room in a building, a free air distributing space at the rear side of said board between the same and the fixed structure of the building, means for supplying fresh air to said space, at least one sound absorbing porous body supported by the rear side of said board between said walls,'said board having sound permeable slots therein between the walls whereby said slots are in communication with the sound absorbing porous body, each of said walls being provided with a passage extending throughout the length thereof and said board having apertures therein registering with said passages, thereby defining a communication path between the free air distributing space and the interior of the room.

2. A sound absorbing unit'or panel, comprising in combination an external board of hard material, spaced transversely extending Walls-on said board arranged perpendicularly thereto, at least one sound absorbing body having a front side and a rear side supported by the board between the walls with the front side facing the board, said board being provided with sound permeable passages between said walls whereby the passages are in communication with the sound absorbing body, each of said walls having a channel extending throughout the length thereof and said board being provided with air permeable passages communicating with said channels thereby defining air passageways leading from the front of the board to a point rearwardly of the sound absorbing body.

of sound absorbing material-having a front side and a rear side supported by the board between the walls with the front side facing the board, said board having sound permeable passages between said walls whereby said passages are in communication with the body of sound absorbing material, each of said walls of moulded material being provided with a channel extending throughout the length thereof and said board further having air permeable passages communicating with said channels thereby defining air passageways leading from the front of the board to a point rearwardly of the body of sound absorbing material.

4. A sound absorbing unit or panel, comprising in combination a board of reinforced moulded material, integral transversely extending strengthening braces at one side of said board arranged perpendicularly thereto, sound absorbing bodies supported by the board between said braces, said board having sound permeable passages between the said braces whereby said passages are in communication with the sound absorbing bodies, each of said braces being provided with a channel extending throughout the length thereof and said board further having air permeable passages communicating with said channels thereby defining air passageways leading from the front of the board to a point rearwardly of the sound absorbing bodies.

5. A sound absorbing unit or panel, comprising in combination an external board of reinforced moulded material, integral transversely extending strengthening braces at one side of said board arranged perpendicularly thereto, sound absorbing bodies supported by the board between said braces, said, boardbeing provided with sound permeable passages between said strengthening braces whereby said passages are in communication, with the sound absorbing bodies, a cover of moulded material at the rear side of said sound absorbing bodies, said cover being integral with and extending from one brace to another, each of said braces being provided with a channel extending throughoutthe length thereof and saidboard further having air permeable passages communicating with said channels thereby defining. air passageways leading from the front of the board to a point rearwardly of said cover.

PER ANDERS PALMER.

REFERENCES CITED The following referencesare of record in the file of this patent:

UNITED: S'IHATES PATENTS Chipley Sept. 7, 1943 

